Answer / vivek anand

Let us understand by taking some example.

let say heater is of 500w and 250v

Bulb 100w and 250v

now, calculate the R

P = V^2/R

SO

R = V^2/P

R1 (heater) = 250 * 250 /500 = 125 ohm

R2 (bulb)= 250 * 250 /100 = 625 ohm

Now, as the question says, they are connected in series, lets find out the current drawn by the circuit

I = V/R

LET THE CIRCUIT CONNECTED WITH 250V SUPPLY

I = 250/(125+625) (R ARE IN SERIES)

I = 0.33A

THIS IS THE AMOUNT OF CURRENT DRAWN BY CIRCUIT IN CONFIGURATION 1.

power of heater = I^2*R*T (TAKE T = 1 hr)

P = 0.33*0.33*125*60*60 = 495 ~ 500w

Now, replace 100w bulb with 40w bulb

R2 (bulb)= 250 * 250 /40 = 1562.5 ohm

New Resistance of circuit will be

R'= 125 + 1562.5 = 1687.5

**NOTE "THE CURRENT IN SERIES IS ALWAYS SAME" and "THE CURRENT DRAWN BY THE CIRCUIT DEPENDS ON LOAD (RESISTANCE)"

In this case we change the load form 750 ohm to 1687.5 ohm, so definitely the current drawn will change.

Now, I' = 250/1687.5 = 0.148 A

now this current will same in the circuit for both bulb and heater bcoz they are in series.

NEW POWER OF HEATER

P = 0.15*0.15*125*60*60 = 101.25

so

OUTPUT DECREASES

Answer / sunil shrivastava

decrease

Answer / sivakumar

out put of the heater decreases because 100watts bulb takes more power then 40 watts bulb. 100 watts produces more heat then 40 watts bulb.

Answer / sarfraj palegar

in this condition heater output will increases
lets take a example and heater resistance X ohms
voltage =current*resistance
in first condition resistance in cercuite is high thats why
current low compare to 2nd condition
in 2nd condition this higher current passes throug circuit
as per formula of heat
H=I2RT
heat output will increases

Answer / yogesh kumar

remains same

Answer / syed ali raza naqvi

output same because in series current is same.in every
point and voltages different.

Answer / roopesh

P=(I^2)R

In series circuit the current is same. So in series circuit power(p) is proportional to resistance(r), therefore 100w bulb has more resistance compare to 40w bulb.

Answer / alok das

If the 100w buld is replaced by a 40w buld then the output
of the heater is increase.

Answer / erick atienza

Since the connection is in series, it will increase because the the current will increase.

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